Let’s talk about sleep

Data suggests that over the past several decades, we have been getting less and less sleep. Work takes priority in many people’s lives, which means that social and family life is reduced to late evenings and weekends. Sleep, for many, seems like a luxury that few can afford. In our performance-centred world, sleeping may even be seen as a sign of laziness and  weakness. At the same time, many really want to sleep, but for many reasons both external (e.g. noise disturbance) or internal (e.g. anxiety and worries) just can’t. In some studies, only 3% of children were found to be getting the minimum recommended 9 hours of sleep per night. It is commonly understood that we are supposed to get 7-9 hours of sleep every night. But who says? Is it really that important? After all, many claim to have trained themselves to get by with just 5 or 6 hours. Margaret Thatcher famously managed to run a country on just 4 hours sleep per night. So, what – if anything – is sleep good for?

How does sleep work?

Sleep is controlled by two distinctive processes that operate independently of each other – circadian rhythm and build-up of sleep pressure. The circadian rhythm is our built-in 24-hour clock, also often referred to as the “body clock”. It determines when we wake and sleep, but also controls many other body processes, such as hunger and thirst, mood and emotions, urinary volume, body temperature, hormone secretion, blood pressure and the metabolic rate.

Sleep cycles

As we sleep, our brain alternates between two phases of sleep, NREM (non-rapid eye movement), which dominates in the early stages of sleep, and REM (rapid eye movement) sleep, which becomes more dominant in the later stages.

NREM sleep identifies and removes unnecessary neural connections and memories in the brain, creating room for new ones. It is during NREM sleep that new memories are transferred from short-term to long-term storage. It also promotes tissue renewal and repair through the release of growth hormone, and immune activity is greater. Going to bed late shortens the NREM phases and thus affects how well the above processes can be carried out.

REM phases are our dream phases, when the brain is as active as if we were awake. At this time, most muscles are paralysed to prevent injury when dreaming. REM creates and strengthens new neural connections, using the space freed up by the decluttering during NREM sleep. REM sleep is required to restore the mind more than the body and by facilitating learning and memory, it is crucial to the development of our emotional IQ and fuels creativity as new links are formed between unrelated pieces of information.

If we go to bed too late, we cut off NREM sleep, which reduces the opportunity for tissue repair. If we wake up too early, we cut of REM sleep, which reduces the opportunity for learning, memory, creativity and mental recovery. NREM and REM sleep are not evenly proportioned. About 75% of our night is spent in NREM, 25% in REM sleep.

We all have experienced sleep deprivation in our lives, but there comes a point when all we can do is lie down and sleep. After a good night’s sleep, we feel infinitely better and we are ready to face another day. This is the benefit of sleep everyone knows about. But are there others?

Sleep and the cardiovascular system – Short sleep has been associated with an increased risk of heart attacks and all-cause mortality. Many people with cardiovascular disease often suffer from sleep apnoea as well. It is not yet clear whether sleep apnoea actually causes heart disease, but we do know that people who have it are at a significantly higher risk. The lack of oxygen caused by the interrupted breathing in sleep apnoea causes blood pressure to go up in an attempt to increase oxygen in the blood. When sleep apnoea is treated, blood pressure often normalises. Obesity is a major risk factor for sleep apnoea, but it is not a condition and are unlikely to be tested for it if they are not overweight or obese. Sleep  apnoea, therefore, may be even more common than we know. Obstructive sleep apnoea is linked to depression as well.

Gastro-intestinal issues – There is no doubt that gastro-intestinal complaints are associated with disrupted sleep. People with insomnia report more digestive problems than those without  (33.6% versus 9.2%) and, conversely, people with GI conditions report more insomnia than those without them. It can be hard to distinguish what came first though. It has recently been discovered that cells in the intestine have a circadian rhythm that influences gut motility, nutrient absorption and metabolism as well as cell proliferation. If the circadian rhythm is disturbed, the intestine is more vulnerable to injury and less able to recover. Considering this  information, it is easy to understand why sleep deprivation has been linked to many gastro-intestinal problems and even colorectal cancer.

A lack of sleep activates immune function, thereby increasing levels of pro-inflammatory compounds such as cytokines, which generate an immune response. This suggests that sleep deprivation would exacerbate any kind of inflammatory and/or auto-immune condition.

A good night’s sleep enables a prolonged fast and a thorough cleaning of the gut – another good reason not to eat too late or to snack after dinner since Every time we fast, the peristaltic movement of the small intestine keeps going to remove any remaining debris once the process of digestion and absorption has been completed in order to ‘rinse’ it. Eating interrupts this important cleansing process.

Sleep and the endocrine system

• As with digestive problems, thyroid issues can also affect how well we sleep and at the same time be exacerbated if we experience sleep disturbances for other reasons. Thyroid-stimulating hormone (TSH) increases before going to sleep and continues to rise over the course of the night. It then decreases during the day. Chronic sleep deprivation can weaken adrenal function and as adrenal and thyroid hormones work hand-in-hand, the thyroid may have to take on more work, which in the long run can also contribute to thyroid dysfunction.

• The connection between sleep and adrenal (dis)function becomes abundantly clear if we look at the involvement of cortisol and the circadian rhythm. Stress triggers cortisol secretion and as a result, cortisol levels may be too high at night to get to sleep. If then we don’t sleep very well, the sleep deprivation is an additional stressor, increasing cortisol, which in turn may then still be too high when the next evening arrives and so the vicious cycle is perpetuated. Relaxation techniques such as mindfulness, meditation, breathing exercises and yoga are known to stimulate the parasympathetic nervous system and help reduce cortisol levels.

Sleep deprivation is an often overlooked, yet significant risk factor for type 2 diabetes (T2D). Lack of sleep has a profound effect on hormone levels (adrenal, thyroid, and reproductive hormones), and T2D is also a hormone-related condition.

Sleep and the reproductive system – Sleep affects fertility in a number of different ways. The HPA axis directly affects reproductive hormones, and other stress-related hormonal pathways affect menstruation, ovulation, conception, implantation, and the ability to carry a foetus to term. As sleep deprivation increases stress, and stress promotes sleep deprivation, getting a good night’s sleep every night has to be a priority for all women wishing to conceive. High levels of TSH cause a number of issues as well. Sex hormone balance depends on the circadian rhythm and its disruption is known to affect reproductive  hormones, as has been observed in shift workers, where women who work night shifts are more likely to have fertility issues.

Melatonin, a key circadian hormone, is also associated with fertility. Testosterone is generally low in women of reproductive age: if high, fertility is impaired and it puts women at a higher risk for sleep apnoea.

Sleep and the nervous system – Research shows that some form of sleep disruption is present in nearly all psychiatric disorders. Sufficient REM sleep is needed for robust mental health, and cutting sleep short – especially at the end of the night – means cutting REM sleep short.

• Sleep deprivation promotes anxiety and depression, which in turn exacerbates sleep deprivation – another vicious cycle. When we don’t achieve the 7-9 hours of quality sleep we need, it can heavily influence our outlook on life, energy level, motivation, and emotions. Even small levels of sleep deprivation over time can chip away at our happiness: we feel less enthusiastic, more irritable, or even have some of the symptoms of clinical depression, such as feeling persistently sad or empty. All these alterations to our mood can affect not only our individual mental health, but relationships and family dynamics as well. Research shows that insomniacs are up to 10 times more likely to suffer from clinical depression, and 17 times more likely to experience clinical anxiety.

• Lack of sleep can also affect the development of Alzheimer’s disease and dementia in individuals.

  
  

A few tips for getting a good night’s sleep:

– Set a schedule – go to bed and wake up at the same time each day.– Exercise 20 to 30 minutes a day but no later than a few hours before going to bed.– Avoid caffeine and nicotine late in the day and alcoholic drinks before bed.– Relax before bed – try a warm bath, reading, or another relaxing routine.– Create a room for sleep – avoid bright lights and loud sounds, keep the room at a comfortable temperature, and don’t watch TV or have a computer in your bedroom.– Don’t lie in bed awake.  If you can’t get to sleep, do something else, like reading or listening to music, until you feel tired.

See a doctor if you have a problem sleeping or if you feel unusually tired during the day.  Most sleep disorders can be treated effectively. I help loads of clients improve their sleep and feel amazing. Please book a free chat with me if you’d like my help.

If  we live to be 75, we will have slept for approximately 25 years of this!

Carrie Cannon – Certified health coach, Masters in Public Health, Registered nurse (UK/Lux)www.carriecannonhealth.com@ CarrieCannonCoaching